Surprise in Space

April 11, 1991

Scientists live and work every day under the pressure of a simple proposition: just when you think something's been settled for good, nature serves up a monkey wrench. Critics of manned orbital exploration of space should take a long look at what happened this week when the shuttle Atlantis got ready to loft into orbit the 17-ton, $617-million Gamma Ray Observatory.

A communications antenna boom jammed. Had the shuttle program been scrapped, as many observers advocated after the 1986 Challenger tragedy, this could have been catastrophic. While a multi-stage rocket could have placed the satellite in orbit, there would have been no shuttle and no astronauts to undertake manual repairs. Fixing problems by remote control is surely possible, as NASA scientists have repeatedly shown with planetary probes, but it is by no means certain. This time, astronauts made an unscheduled spacewalk to jiggle the boom and deploy the satellite.

This may have saved the observatory's two-year mission to map high-energy gamma rays that carry clues to such puzzles as exploding stars and black holes. The observatory may also help astronomers unravel the mysteries of a recently discovered super-massive object in a bright galaxy 300 million light-years away. Using the 88-inch telescope atop Hawaii's Mauna Kea volcano, an astronomy team has found what appears to be galaxies in collision, with one revolving around a dark object thought to be as massive as the entire Milky Way galaxy.

The researchers -- the University of Maryland's Andrew S. Wilson, Rice University's Joss Bland-Hawthorn and R. Brent Tully of the University of Hawaii -- say it may be the biggest of a whole crop of suspected black holes, those enormously dense concentrations of mass and gravity that scientists would like to probe.

Astronomers looking with new tools such as the Rosat X-ray satellite and the Gamma Ray Observatory could make vast leaps in their understanding of the universe. During the life of the observatory, scientists plan a survey of the skies that will allow them to pinpoint many targets for major study. Manned space flight proved its worth during this shuttle mission. The crew's two spacewalks, totaling more than six hours, also may pave the way for an even more ambitious manned project on NASA's drawing board -- construction of a $30-billion space station later this decade.